Interdot Coulomb correlation effects and spin-orbit coupling in two carbon nanotube quantum dots
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)
Transport properties of the two-level Kondo effect involving spin, orbital, and pseudospin degrees of freedom are examined in a parallel carbon nanotube double quantum dot with a sufficient interdot Coulomb interaction and small interdot tunneling. The interdot Coulomb correlation effects are taken into account, and it plays an important role in forming bonding and antibonding states. Attached to ferromagnetic leads, the Kondo effect is observed at the interdot Coulomb blockade region with degeneracy of spin, orbital, and pseudospin degrees of freedom. A crossover from a two-level Kondo state involving the fivefold degeneracy of the double quantum dots to an SU(4) spin-orbit Kondo state and to an SU(2) spin-Kondo effect is demonstrated. At finite magnetic field, the splitting of the spin, orbital, and pseudospin Kondo resonance can be restored. For finite intradot Coulomb interaction U, there is a competition between the single-dot Kondo effect and the antiferromagnetic exchange coupling J{sub AFM}, resulting in the suppression of the Kondo resonance. Moreover, both the J{sub AFM} and the Zeeman interactions compete, leading to need a much higher value of the magnetic field to compensate for the Kondo splitting.
- OSTI ID:
- 22275653
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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